Stunning new photos show the faces of animals on the verge of extinction

Flach's images often capture creatures' moods, expressions, and gestures in ways that make us rethink our relationship with the natural world.

His newest book, "Endangered", includes text by zoologist Jonathan Baillie and tries to make readers consider the impact they have on these animals — and consider what it would mean for them to disappear.

Along with the creatures themselves, Flach photographed the landscapes these animals live in.

He spent days in frozen snow to capture a shot of the rare Siaga antelope. He swam with sharks and hippos, and visited zoos for perspectives of wildlife in settings created by humans.

The ecosystems in which many of these creatures live have already been destroyed to make room for cities and farms. But by eliminating such habitats, we remove the only places some of the most unique creatures on Earth can live.

Check out a selection of some of our favorite photos from the book below.

Pangolins are one of the creatures most threatened by the illegal wildlife trade. This white-bellied pangolin can be seen hanging from its mother's tail.

Hippos are hunted for their meat and their ivory teeth.

Yellow-eyed tree frogs are affected by climate change — they're threatened by a fungus that's spreading through forests, and their eggs are hatching early or late because they're sensitive to temperature.

Ploughshares are the rarest tortoises in the world — these were photographed at a breeding sanctuary.

Yunan snub-nosed monkeys were believed to be extinct before one was spotted in 1962 — though the remaining populations are small and isolated.

Fireflies are helping us learn how bioluminescence works, though light pollution and loss of forests threaten these creatures.

The Philippines has started to employ indigenous people to replant the forests that Philippine eagles live in, and to try to prevent poaching.

Carrion-eaters like these whiteback vultures suppress the spread of disease and alert game wardens to poachers. But some poachers have started poisoning their kills in order to eliminate the endangered birds that draw attention to illegal hunting.

Snow leopards, among the most elusive cats in the world, are losing their habitats as forests move up the slopes in the warming Himalayas.

Saiga antelope have survived since the ice ages — the species has shared the world with woolly mammoths and saber-toothed cats. But catastrophic disease and poaching have put the species in a critical place.

It used to be possible to find 16-feet-long Beluga sturgeon in and around the Black and Caspian Seas. But those giants are gone, and the small ones still around are threatened by people who harvest their valuable eggs.

Sudan, pictured here, is the last male northern white rhinoceros in the world.

Another photo of Sudan, taken by biologist Daniel Schneider, recently went viral. That image also showed the rhino with his eyes downcast.

"Want to know what extinction looks like? This is the last male Northern White Rhino," Schneider tweeted. "The Last. Nevermore."

Stunning new photos show the faces of animals on the verge of extinction

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